1. Field of the Invention
The present invention relates to a train control system, and more specifically, relates to a train control system that can obtain information about distance between trains and can obtain information about distance between trains from a device other than a ground device, to enable safer travel control of trains.
2. Description of Related Art
Conventionally, in a train control system using a so-called radio distance measurement system, a vehicle radio set is mounted on a train, and a wireless network is formed between the vehicle radio set and a plurality of wayside radio sets, which is spatially separated and disposed along a wayside of a track on which the train travels, and then, a wireless propagation delay (time) between an on-board antenna of the vehicle radio set and a wayside antenna of the wayside radio set is measured, to detect a train location, so that the train control is performed based on the detected train location.
Furthermore, as such a train control system using the radio distance measurement system, conventionally, for example, a technique including: a wireless train location detecting unit that detects a train location on a predetermined track based on a propagation time of a radio wave between a vehicle radio set mounted on a train travelling on the predetermined track and a ground radio set disposed at a predetermined location on the ground; a travel distance calculating unit that calculates a travel distance of the train on the predetermined track based on an output signal of a tachometer generator connected to an axle of the train; a temporary reference location setting unit that sets the detected train location detected by the wireless train location determining unit as a predetermined temporary reference location; and a train location detection calculating unit that detects a train location on the predetermined track based on the travel distance calculated by the travel distance calculating unit based on the temporary reference location set by the temporary reference location setting unit, has been disclosed (see, Japanese Laid-open Patent Application Publication No. 2007-331629, for example).
However, in the conventional technique, a location of a train is detected and a ground device transmits the train location information to an on-board device; however, for example, when a wireless communication state with wayside radio sets is unsatisfactory, or when no communication equipment can be disposed along a wayside of a track, the train cannot receive sufficient information, and accordingly, sufficient travel control of the train cannot be performed based on only the train location information provided from the ground device, and thus, there is a need for an alternative communication system.